Variable-pitch pulley



l, D. M. wA'rsoN 2,172,230

VARIABLEPITCH PULLEY md Dec. -12, 195e Sept. 5, 1939.

F167; L :j

INVENTOR:

Baz/id Mmmm,

Patented sept. s, 1939- UNITED STATES vAmAnLE-rircn PULLEY David M.Watson, Ardsley, Pa., assignor'to The American Pulley Company,Philadelphia, vPa., a corporation of Pennsylvania application December12, 193s, serial No. 115,491

The primary object of this invention is the provision of a pulley of thekind above indicated including a rotary member adapted to affectconcurrent approach or receding' of the pulley groove-forming componentsrelative to one another.

Another object is the provision of a multigroove variable-pitch pulleyin which the several 15 groove-forming components lare concurrentlymovable to vary the effective diameter of said pulley without disturbingthe respective centers of the belts being driven thereby.

A further object is the provision of a variablepitch pulley of the typeindicated comprising but few parts which are simple to construct, andwhen assembled are easy to manipulate for changing the active diameterof the pulley; while being immune to relative movement when set at therequired adjustment.

Other objects and advantages, more or less ancillary to the foregoing,and the manner inwhich they are realized, will become apparent from anexamination of the following description which, considered in connectionwith the accompanying drawing, sets forth a preferred embodiment of theinvention.

Generally stated, this invention consists yof the novel items,combinations of means and arrange- 85 ment of the parts hereinafterdisclosed, illustrated by the drawing, and more concisely expressed inthe claims at the conclusion of this specication.

In the drawing: 'y Fig; I is a view of the improved pulley, partly inelevation and partly in section, as viewed in the direction of theplane-designating arrows I-Iin Fig. II. V

Fig. II is a section on the plane marked II-lI 45 in Fig. I. Y

Fig. III is a fragmentary sectional view, taken as indicated by thearrows III-III in Fig. II.

Fig. IV is a perspective view of a sleeve hub member hereinafterparticularly/ described; and,

Fig. V is a perspective view of an adjusting collar, likewise later onfully explained,

In all the views, corresponding parts are designated by like referencecharacters.

Referring more in detail to the drawing. the numeral I designates abroken portion of a drive shaft. 2 a sleeve pulley-hub which is heldagainst rotation relative to said shaft by a spline 3 and securedagainst axial movement by a set-screw 4. The hub 2, as best understoodfrom Fig. IV, in-

cludes a cylindrical sleeve-like main portion 5 5 l with an enlargement6 at one end radially apertured and screw-threaded at 1 for passage ofthe set-screw 4 aforesaid. Remote from the enlargement 6, thesleeve-like main portion 5 is reduced to form a shouldered abutment 8,and l further reduced and provided with a right-hand screw-thread at 9for a purpose later on again 'referred to. The bore lof the hub 2 isvlongitudinally grooved at I0 for reception of the spline 3,

and externally formed with an opposing keyl Way Il.

Slidably fitting the hub 2 are a series of longitudinal angle-sectiongroove-forming components I2, I3 and Il, with opposing discouscomponents I5, I6 and I'l, jointly providing V-grooves 20 I8. Attentionisrdirected to the fact that the discous components I6, I 1 Slidably fitthe tubular porions I9 of the components I3, I4; whereas the discouscomponent I5 has a relatively larger bore provided with an internalleft-hand screw- 25 thread for operative coaction with a correspondingexternal screw-threaded -portion 2| of an adjusting collar 22. Thiscollar 22, it is.to be remarked, is formed with an inwardly-projectingportion 23 of a dimension for free rotative 30 movement on the hubshouldered abutment 8, as

-well as an internal portion provided with a righthand screw-thread 24for operative coaction with the correspondingly threaded-exterior 25 ofthe tubular portion I9 of the groove-forming com- 36 ponent I2.

Inl order to prevent rotation of the grooveforming components I2, I3 andI4 relative to the hub 2, use is made of a spline 26 engaging thekeywayII and conformative slots II' through the 40 tubular portions I9 oi'said components; whereas similar displacement of the discous componentsI5, I6 and I'I with respect to the components `I2-II aforesaid isobviated by circumferentiallyspaced screws 21, the heads whereof seat inborings through the disc component I5 and their ends Abeingscrew-threaded at 28 into the disc component I l, with spacers 29intervening the component I6 and said components I5, I1.

'Ihus it will be readily understood the disc com- 5ol ponents I6, I1 arerigidly connected'to the component I5, with capacity for axial movementlon the tubular portions I9 of the components .I2-I4 through the mediumof the adjusting collar 22,

In order to prevent relative circumferential From the foregoingdisclosure it will be clearly apparent that in order `to change thepitch diameter of the pulley, all that is necessary to be done is tosimply revolve the adjuster collar 22,4

which is preferably provided with circumferentialiy spaced holes 34 forapplication of a span-v ner-wrench, in an obvious manner. Revolving orturning of the adjuster collar 22 in a, clockwise direction will movethcA sheave or grooveforming components I2--I4 toward said collarand, atthe same time, move the disc components I 5-I1 away therefrom atacorresponding rate of travel; or, in other words, the grooves I8 willbe contracted with expansion of the eectivediameter of the pulley. v0nthe contrary, when the adjuster collar 22 is rotated in ananti-clockwise direction, a reverse action takes place -between theseveral groove-forming components I2l1 whereby. the eilective diameterof the pulley is decreased and, in both cases, without disturbing thealignmentof the belts driven thereby. The adjuster collar 22 and all ofthe pulley-forming lcomponents are restrained against ain'al shifting atthe required adjustment by the hub shouldered-abutment 8 in onedirection, and by a retaining collar or lock-nut 35 applied to thescrewthreaded end 9 of the hub 2 in the other direction; said nut beingsecured by a drift pin 3B or the like, in accordance with knownpractice.

While a specific embodiment of the invention has been illustrated anddescribed, it is to be understood that alteration in the details ofcon-4 struction may be effected without departing from the spirit andscope of said invention as indicated in the following claims.

Having thus described my invention, I claim: 1. In a variable-pitchpulley, .coaxial grooveforming components movable toward or away fromeach other, one of the said components embodying an externallyscrew-threaded portion and the companion component anl internallyscrewthreaded coaxial oriiice, said screw-threads being dierential,means restraining said components against relative rotation, and anadjuster collar having interior and exterior screw-threads respectivelycooperative with the corresponding external and internal componentthreads to effect their axial separation and vice versa.

2. In a variable-pitch pulley, coaxial grooveforming components movabletoward or away from each other, one of the groove-forming componentsembodying a tubular portion having an external right-hand screw-threadand the .companion component; an axial orice of larger diameter with aninternal left-hand screw-thread, means restraining said componentsagainst relative rotation, an adjuster collar having interior andexterior screw-threads of corresponding pitch cooperative with theexterior and interior threads of the companion components respectively,and said collar includes means for engagement with appropriate stops torestrain -it against shifting in an axial direction. l

'3. A multi-groove variable-pitch pulley comprising serial sheave unitseach including opposed growing-components, the complementalgrooveforming components for each groove embodying tubular portions andone of which is externally screw-threaded, companion components some ofwhich slidably engage the tubular portions of the rst mentionedcomponents and another .is ori- -ced and provided with an internalscrew, threaded ina reverse direction tothat of the tubular portion ofits companion groove former, rigid means vconnecting the 'alternatinggroove-forming components for concurrent axial movement,

and an adjuster member in the form of a collar having inner and outerscrew-threads respectively cooperative with-the external 'and internalscrew threads aforesaid to eiect variation in the pitch diameter of thepulley.

4. A multi-groove variable-pitch pulley comprising serial sheave unitseach including opposed complementa] groove-forming components, one

4series of the complemental groove-forming components embodying tubularportions and one of which-is externally screw-threaded, companionvcomponents lsome of which slidably engage the tubular portionsvof thefirst mentioned components and another is oriilced and provided with aninternal screw, threaded in a reverse direction to that of the tubularportion'of its companion groove former, circumferentially arrangedspacer means rigidly connecting the components having tubular portions,similarly allocated rigid elements connecting the companion elementstogether, and an adjuster member in the form of a collar having innerand outer screw-threads respectively cooperative with the external andinternal screw threads aforesaid to effect variation in the pitchdiameter of the pulley, said collar also embodying aninwardly-projecting portion Ifor coaction with suitable stop means toprevent itsaxial shitting.

5,'A multi-groove variable-pitch pulley comprising a sleeve hub withmeans for restraining it against axial displacement, a plurality ofsheave-forming components.A embodying coaxial tubular portions splinedexterlorly on said hub, a corresponding plurality of opposingsheave-forming axially-oriced components movable over the companioncomponent tubular portions at one side of the pulley, one of the endtubular portibns having an external right-hand screw-thread and thecompanion component orifice being provided with a left-handscrew-thread, an adjuster collar having inner and outer right-hand andleft-hand screw-threaded portions respectively cooperative with thetubular portion and orifice threads aforesaid, means conning said sleeveto rotative movement only -to vary the pitch diameter of the pulley,means 'limiting the oriced sheave-forming components to simultaneousaxial movement, and means for, restraining the adjuster collar and allof the pulley forming components against axiial shifting lengthwise ofthe sleeve hub afores d.

6. A multi-groove variable-pitch pulley as defined in claim 5 whereinthe means conning the adjuster collar to rotative movement comprise aninwardly-projecting concentric portion of said collar rotativelyflttinga shouldered or reduced part of the sleevehub proximate one end, and aretainer-collar threadedly engaging the adjoin- 'ing outer end of saidhub. said latter parts being secured together by a pin driven betweentheir engaged surfaces.

DAVID M. WATSON.

